Here are some I've heard about:

Musketeer: Probably like a pirate/gunner job. Likely too close to Machinist to get added at this point.

Mime: Iirc there is a blue mage carnival npc who is a Mime. Probably won't become playable but would be interesting to have a job that used other job abilities in a specific predetermined way or as a limited job for fun combos.

Mathematician: Clearly a healer. But might be too similar to sage.

Puppetmaster: Melee pet job. No way we're ever getting this as anything besdies a limited job unless they decide to fix how pets work.

Geomancer: Likely a magical support job but could potentially be a healer as well.

Templar: Melee DPS paladin essentially.

Gunhammer: Idk if this job has an official name but it's basically Nero and a few other garleans who use their giant gunhammers. We don't have any hammer jobs yet. It could easily be melee dps or tank.

Any others I forgot to m ention?